Electronic digital thermometer
First Claim
1. A temperature measuring device comprisingoscillator means to which a temperature-sensitive resistive element and a temperature-insensitive resistive element are alternately coupled as a frequency determining element to produce a temperature-dependent frequency fx and a temperature-independent frequency fs alternately;
- and temperature output circuit means coupled to said oscillator means for providing a measured temperature value T on the basis of an equation defined by ##EQU13## where TO =predetermined reference temperatureα
=temperature coefficient of said temperature-sensitive resistive element.
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Abstract
An electronic digital thermometer comprises a pulse oscillator to which a temperature-sensitive resistive element and a temperature-insensitive standard resistive element are alternately coupled as a frequency determining element, a temperature output circuit which is provided with a counter connected to the pulse oscillator and provides a measured temperature value, and a digital display device for displaying the measured temperature value. The temperature output circuit is so arranged that oscillation frequencies of the pulse oscillator respectively produced when the temperature-sensitive resistive element and the standard resistive element are coupled with the pulse oscillator are compared to calculate a measured temperature value.
50 Citations
25 Claims
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1. A temperature measuring device comprising
oscillator means to which a temperature-sensitive resistive element and a temperature-insensitive resistive element are alternately coupled as a frequency determining element to produce a temperature-dependent frequency fx and a temperature-independent frequency fs alternately; - and temperature output circuit means coupled to said oscillator means for providing a measured temperature value T on the basis of an equation defined by ##EQU13## where TO =predetermined reference temperature
α
=temperature coefficient of said temperature-sensitive resistive element. - View Dependent Claims (2, 3, 4, 5)
- and temperature output circuit means coupled to said oscillator means for providing a measured temperature value T on the basis of an equation defined by ##EQU13## where TO =predetermined reference temperature
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6. An electronic temperature measuring device comprising a pulse oscillator including a temperature-sensitive resistive element as a frequency determining element, a temperature output circuit having a counter connected to said pulse oscillator to count output pulses of said oscillator during a given time interval for providing a measured temperature value on the basis of pulse number counted during the given time interval, and a time decision circuit for deciding the pulse counting time of said counter, characterized in that:
- said oscillator is so arranged that the temperature-sensitive resistive element and a standard resistive element which is substantially insensitive to temperature are alternately coupled to said oscillator as a frequency determining element;
said temperature output circuit is so arranged that said counter counts, during the time interval decided by said time decision circuit, pulses produced when at least said standard resistive element is coupled with said pulse oscillator, and a measured temperature value provided by said temperature output circuit is functionally related to the numbers of pulses counted by said counter during the time interval decided by said time decision circuit. - View Dependent Claims (7, 8, 9, 10, 11, 12, 13)
- said oscillator is so arranged that the temperature-sensitive resistive element and a standard resistive element which is substantially insensitive to temperature are alternately coupled to said oscillator as a frequency determining element;
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14. An electronic temperature measuring device comprising:
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a pulse oscillator to which a temperature-sensitive resistive element and a temperature-insensitive standard resistive element are alternately coupled as a frequency determining element to produce first and second output pulses alternately; an up-down counter connected to said pulse oscillator; and means for causing said up-down counter to be counted up from a present value to a given value by said first output pulses of said pulse oscillator produced when said temperature-sensitive resistive element is coupled thereto and to be counted down from the given value, during the same time interval as the time interval required by said up-down counter to count said first output pulses, by said second output pulses of said pulse oscillator produced when said standard resistive element is coupled thereto. - View Dependent Claims (15, 16, 17, 18, 19, 20)
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21. A temperature measuring device comprising:
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oscillator means to which a temperature-sensitive resistive element and a temperature-insensitive resistive element are alternately coupled as a frequency determining element to produce a temperature-dependent frequency and a temperature-independent frequency alternately; temperature output circuit means coupled to said oscillator means for providing a measured temperature value on the basis of a function of the ratio between the temperature-dependent frequency and the temperature-independent frequency produced by said oscillator means; and digital display means coupled to said temperature output circuit means for displaying the measured temperature value. - View Dependent Claims (22, 23, 24, 25)
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Specification